Fearing that he is constantly putting Alicia in danger, Ben decides that it's best that they break-up so that Alicia is no longer in any danger from any of the Fantastic Four's villains. This upsets Alicia who tearfully, and angrily accepts it, and Ben regrets the suggestion right after she slams her door on his face but decides to stick with his decision.

Returning to the Baxter Building, where he helps Reed Richards out in the lab, they are interrupted by the arrival of Walter Newell (aka Stingray) and his colleague Henry Croft. The two men have come seeking Reed Richard's aid, as Henry and a group of people living on Hydro-Base had been turned into amphibians by the villain Dr. Hydro and all their attempts to restore everyone on Hydro-Base to normal have to date failed. After hearing about how Dr. Hydro changed all the people of Hydro-Base into amphibians Reed agrees to help.

Meanwhile, Thundra has gone back to the gym where she was tricked into helping the Grapplers in invading Project Pegasus on the behalf of Roxxon Oil. Inside she confronts her former manager Herkimer Oglethorpe, however before she can get information out of him she is confronted by his bodyguard and sometime wrestler, Hyperion. While out on the New York/New Jersey highway, Aquarian wanders the streets and saves a deer from being struck by a car.

Back at the Baxter Building, Ben is roused from a dull exercise session by Reed Richards, who informs Ben that he found similarities between Dr. Hydro's formula and the Inhuman's Terrigen Mists. Having contacted the Inhumans, they had agreed to give Reed a sample, and so Reed sends Ben, Walter, and Henry to meet Triton in California to pick up the Terrigen Mist sample.

Arriving on the California coast, Walter notices a suspicious looking Roxxon Oil rig, and comments on how it's in a location where there are no oil deposits, Ben simply dismisses it as they land the Pogo Plane in the ocean and wait for Triton's arrival. With some time to kill, Ben and Walter decide to investigate the strange oil rig, Walter changing into his Stingray costume.

When they approach the Roxxon Oil Rig they are asked to leave by the workers, when suddenly an underwater explosion damages and destabilizes the rig's ability to stay afloat. As Ben keeps the rig upright, Stingray jumps into the water and tries to find out the cause of the explosion. To the Thing's surprise, he is attacked by the rig workers, and Stingray finds himself attacked by a bunch of underwater divers.

As the two heroes manage to fight off their attackers, they are suddenly brought to the attention of an approaching submarine. When the sub rises from the water, from its exit hatch comes a new group of costumed super-villains: The Serpent Squad.

Dr. Croft mentions the time Doctor Hydro mutated him and the crew of an aircraft turning them into the Hydromen, this happened in Sub-Mariner #61.

Stingray mentions his previous encounter with Triton of the Inhumans in Sub-Mariner #31.

The theory that there might be a connection between the Inhumans and the Hydromen turns out to be true. As revealed in Marvel Two-In-One #71 the gas that Dr. Hydro used was derived from the Terrigen Mist that is used to empower the Inhumans.

Thundra recalls her brief wrestling career and how she got swindled into working for Roxxon to infiltrate Project PEGASUS, this was chronicled in Marvel Two-In-One #53-58.